Polyolefinic materials are widely used in industry for a large variety of different applications. In particular their low cost and their versatility have led to polyolefins replacing conventional material from metal to rubber and have further led to polyolefins making entirely new applications accessible.
A great proportion of the specific material properties of polyolefins stems from the fact that such materials are not entirely crystalline but rather comprise crystallites of varying size. Many macroscopic properties can be linked to size of the crystallites more or less directly. One such property is the stress strain behaviour; the tensile forces required to strain the material need to be higher if the size of the crystallites become larger. Another macroscopic property linked to the size of the crystallites is the colour or transparency of the material. If the crystallite sizes are of the same size as the wavelength of visible light, the light is dispersed.
It is further known that an increase in molecular weight leads to: an increase in required tensile forces for straining the material; a higher melting temperature; improved compressive creep; improved hysteresis properties; and other changes. This is at least in part due to an increase of entangling between the molecules.